Peak exercise left ventricular function measured by radionuclide angiography (RNA) is known to have strong prognostic value and therefore can be very helpful for screening patients with a low to intermediate likelihood of CAD. The technique has seen little clinical use, however, because of the inadequacy of current methods for correction of motion artifact produced by treadmill exercise. In the Phase I study, a novel technique of motion correction was developed using a combined ultrasonic/intertial position tracking system along with the previously developed multiwire proportional camera. High quality motion corrected treadmill images were obtained both in laboratory tests and in a group of patients at Cornell-New York Hospital, proving feasibility of the technique. The Phase II work will involve substantial development, including improved image correction and clinically convenient acquisition, correction, and display software as well as refinement of the structural design and mechanical assembly of the system. Prototype systems will be constructed and placed in two well-established nuclear cardiology laboratories. Clinical studies will be performed in a total of 600 patients to establish the normal response for the new technique in low risk patients and to assess the use of the test for screening this population. As a very practical, low-cost test, the motion corrected treadmill angiography system can greatly improve risk stratification of suspected CAD patients and decrease the frequency of false positive diagnoses. As a result, far fewer patients would be unnecessarily shuttled into expensive and invasive diagnostic tests such as SPECT imaging and cardiac catheterization, greatly reducing cost in the prodigious process of coronary disease diagnosis. PROPOSED COMMERCIAL APPLICATIONS: Current diagnostic tools for stratification of CAD patients have substantial technical and/or financial drawbacks. A motion corrected treadmill nuclear angiography could serve as a highly accurate front-line screening mechanism to be incorporated in the decision-making tree. Because of the huge number of patients who report mild to moderate symptoms/risk factors but show normal perfusion and cath results, a technique which identifies appropriate candidates for further evaluation would have a large commercial market and significantly reduce unnecessary spending of precious heath care dollars.